Self-expanding stents are designed for deployment using which mechanism?

• A. Premounted on a self deployment catheter
• B. Inflated by a high-pressure balloon only
• C. Requires external magnets
• D. Color-coded for compatibility only

Answer: (A)

Self-expanding stents expand on their own once released from a constrained delivery system. They’re typically made of a shape‑memory material (like nitinol) that is compressed inside a delivery catheter and held by a sheath. When the sheath is withdrawn, the stent decompresses and springs to its preset diameter, pressing against the vessel walls. This is the mechanism implied by being premounted on a self‑deployment catheter—the stent is carried in a constrained state and “lets go” to expand without balloon inflation.

Inflating with a high-pressure balloon is how balloon-expandable stents operate, not self-expanding ones. External magnets are not used to deploy stents, and color-coding is for labeling and compatibility, not the deployment mechanism.